Telephone system.



PATENTED JAN. 1, 1907.

H. G. WEBSTER.

TELEPHONE SYSTEM.

uruoumn FILED DEO.12.1902.

UNITED STATES PATENT OFFICE.

HARRY Gr. WEBSTER, OF CHICAGO, ILLINOIS, ASSIGNOR TO KELLOGG SWITCHBOARDAND SUPPLY COMPANY, OF CHICAGO, ILLINOIS, A

CORPORATION OF ILLINOIS.

TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented Jan. 1, 1907.

To a whom it may concern.-

Be it known that I, HARRY G. WEBSTER, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented a certain new and useful Improvement in Telephone Systems, ofwhich the following is a specification' My invention relates totelephone systems of the common-battery type in which provision is madeat the central office for variously connecting the subscribers togetherfor conversational purposes and in which suitable apparatus is providedfor supervising established connections.

This invention has for its objects the simplification of the circuits,connections and arrangements by which the above-mentioned operations areaccomplished, and the provision of a system in which the said operationsmay be carried out in a rapid, positive, and efficient manner.

In the accompanying drawing, in which the same reference charactersindicate similar parts throughout, the figure is a diagram of twosubscribers lines and the central-oflice apparatus employed inconnecting the lines together.

L and L indicate telephone-lines extending from their respectivesubstations to the central oflice, the former line being shown as asingle-station line, while the latter is indicat-ed as of thepolystation or party-line type. At the station A, located on the line L,the two line conductors 2 and 3 are preferably permanently bridged by anordinary polarized call-bell 4 and a condenser 5, while anormally openbridge of the line conductors ineludes the transmitter 6, receiver 7 andthe switch-hook 8. At the central office the tip conductor 2 permanentlyincludes the winding of the line-relay R and is then'connected by aconductor 9 with the live pole of the cen tral and common battery B, theother pole of which is grounded. The other line conductor is connectedwith the spring 10 of the cutoff relay R for the line and is therebynormally grounded through the branch conductor 11.

The individual signal for the line preferably consists of a smallincandescent lamp S, which is energized from the battery B orothersuitable source and has its local circuit controlled through thenormally open contacts of the line-relay R, as well as through thenormally closed contacts of the cut-off relay R a conductor 12 extendingbetween one of the normally open contacts of the linerelay R to one ofthe normally closed contacts of the cut-off relay R Suitableconnec-tion-terminals, preferably in the form of spring-jacks J, J and Jare provided in multiple before the operators and have theirtip-contacts joined by conductor 13 with the line conductor 2, While thesleeve-contacts of said jacks are conductively connected by conductor 14with the. forward contactof said spring 10 of the cut-off relay R Thewinding of the cutoff relay R is connected between the conductor 14 andthe tip-conductor 2 or its continuation 13.

The line L is provided at the central office with exactly similarapparatus as employed. in connection with the line L, except that a,common lead or omnibus bar 9 extends to the live-pole of a second commonbattery or other common source of steady-current B The talkinginstruments at the substations are also connected in a normally openbridge of the line conductors; but the call-bells are placed in groundedbranches from either side of the line and preferably from the normalcontacts of the hook-switches.

At the central oflice the operators are provided with any desired numberof cord-circuits, each of which includes an answeringplug P and thecalling-plug P having tip and sleeve contact-surfaces adapted tocooperate with the like contact surfaces of the connection terminals orjacks of the lines. The tip-contacts of the plugs of each pair areconnected together by the flexible strands t and t and the interposedcondenser 0, while the sleeve-contacts are likewise conductively joinedby the similar strands s and s and the interposed condenser 0 Thebattery B is bridged across the answering end of the cordcircuit andincludes in its connection therewith upon either side the tipsupervisory relay and the sleeve supervisory relay 1, which control, theformer through its normally closed contacts and the latter through itsnormally open contacts, the local circuit of the supervisory signal Swhich is preferably energized from the said battery B. The calling endof the cord-circuit is similarly connected with the battery B uponeither resistance of anaverage line. It will be un derstood, however,that the relative proportions may require modification under different'conditions of use.

vides a new Forthe pur ose of testing the busy oridle condition'of tietelephone-lines the branch which connects the supervisory relay r with.-

thetip conductor 2 is normally severed at the spring 15 0f the sleevesupervisory relay 7", which spring is normally connected'with thebranch16, permanently connected with said tip-strand, while theremaining portion 1.7 of

the connection of said relay with the tipstrand is connected with theforward contact of said relay-spring 15. The normal contact of saidspring is connected by conductor 18 With the preferably high-resistanceand higheimpedance test-relay r which is joined by conductor 19 to thepoint20, located uponconductor 21, that is connected with the lead 9.This test-relay is preferably common to the cord-circuits belonging toeach operator. The said conductor 21 includes the retardation-coil 22,the operators transmitter 23', and is thence grounded- The primarywinding ofthe operators induction-coil 24 and a condenser c areconnected in shunt of the transmitter 23. The grounded spring of saidtest-relay closes through its forward contact'a conductive path from apoint on said shunt between the condenser c and the said primarywinding. The operator s receiver 25, the secondary of her induction-coil24, and a condenser c are adapted to be bridged across the calling endof the cordcircuit by the springs 26 of a suitable listening-key.

Aringing-generator 27 is-connectedon one side .to ground and upontheother side isarranged to deliver negative pulsating current through asuitable resistance-lamp over conductor'28r to the tip side of the lineand also to furnish alternating current. through a suitable -lamp overconductor 29 with the sleeve side of the cord-circuit andthe-telephoneline- The depression of the springs 30 of the ringingkey,therefore, connects the generator with the tip-strand of thecord-circuit while the sleeve-strand is grounded, and the operation ofsprings 31 of the said. key connects the generator with thesleeve-strand and propath for current from the battery B over thetip-strand through conductor 32 and the fifty-ohm coil 33.

The operation is as follows: Taking up the receiver at the station Acloses the line conductors together, with the result that current flowsfrom the live pole of the battery B, over the lead 9, through theline-relay R, thence over the line conductor 2, through the substationinstruments, and back to the central ofli'ce, over the line conductor 3,and through the spring 10 and branch 11 to ground. The current in thispath energizes the line-relay R, which closes the local circuit ofthesignal lamp S and permitscurrent toflow therethroughfrom the lead9,throughthe closed contacts of the line-relay R, and'thence overconductor 12, the spring 1O ofcut-oifrelay R and branchll to ground. Theoperator observing the line-signal inserts the answer'- ing-plug P intheanswering-j ack J, withthe resultthatthe battery B is included-in alocal circuit withthe cut-off relay R saidcircuit including thetip andsleeve-strands-of*the cord-circuit and the jack conductors 13 and 14.Although of high resistance, thiscutoff relay is adjusted torespondzto'current over this pa-th'even though it is shunted by the lineconductors. Its operation cuts off the ground branch 11 and also opensthe local circuit of the line-lamp S; The linerelay R also opens thecircuit of the signal S for the reasonzthat it is shunted by thesupervisory relay 7". The supervisory relay-r is: energized overthe samepath as the cut-off relay R and closes the local circuitzofthe su-'pervisory lamp S This lamp does not' light, however, on account of theoperation-of the tip-relay 1", which serves to open-this circuit. Thesleeve-relay r is adjusted to respond/to the current flowing throughitwhether or not the subscribers line is open, whereby it serves toclose the circuit of the1-lamp*S while a connection is up. Thesupervisory relay 1 is adjusted to respondonly to the current flowingthrough it when the subscribers instrument is in use, whereby assoon asthe line-circuit is opened by the return ofithere ceiver to its hookthesaid-relay ismleenergized and the lamp lighted. Upon receiving theorder forthe connection the operatorrtests the condition ofthewantedline.- Under nor-- mal conditions it will beseen that the testrings ofthe jacks are connected through the conductorl l, the winding'of thecut-off relay R and thence by leads 9 or 9 With the live pole ofabattery. Inasmuchas thewtip of the cord-circuit iselikewise-connectedand is raisedto the full potentialof the battery, no

click will be received when an idle line is tested. If a plug has beeninserted in any of the jacks of the line, this. connects the testringsthereof with the grounded pole: of-a battery, so that the applicationofthe tip of a testing plug to a diflerenttest ring of the line wouldcause a flow'of current over the tip- ICC 6 5 battery B similarlyprovides the line L with 1 ing cord strand and would cause a click inthe operators receiver. This click is caused in the following manner:The testing-current flows over the tip strand, spring 15 of supervisoryrelay 1*, conductor 18, through the test-relay r conductor 19, andconductors 21 and 9 to the live pole of the batery. The testrelayresponds to this current and closes a ground branch from the operatorsshunt, which permits a flow of current through the primaryof'her'induction-coil. Upon finding the line idle a calling-plug isinserted in the jack and the ringing-key operated. The operation of thesprings 31 connects the generator with the sleeve conductor, therebysending alternating current out over the sleeve side of the line andthrough the bell at the stationC, thus operating the same. At the sametime the tip-spring 31 connects with the conductor 32 through the coil33, and thus provides an auxiliary path for current through the cut-offrelay to maintain the same operated and a low-resistance return-path forringingcurrent in case the subscriber answers during ringing or incasethe said springs are operated for calling a single subscriberlocated upon ametallic line. The operation of the tipsprings 30 connectsthe generator with the tip line conductor to operate the bell at stationD, while the sleeve conductor is grounded to provide a low-resistancepath. This ringing-current is, moreover, pulsating in character, wherebythe cut-off relay is readily held up by the same, and it is preferablyof the same polarity as that impressed upon the line by the battery BAfter ringing and before the subscriber responds the sleeve supervisoryrelay r operates to dis connect the test-relay and complete theconnection between conductors 16 and 17 through the relay r At the sametime the relay 1* closes the local circuit of the super visory lamp Sand since the relay r is not yet operated the said lamp is lighted toindicate the fact of the non-response of the subscriber to the operator.As pointed out, the cut-off relay R and the supervisory relay r are nowincluded in alocal circuit with the battery B said local circuitincluding two parallel branches, one leading through the line-relay Rand the other through the supervisory relay r These relays are soadjusted that under these conditions the supervisory relay r and thecutoff relay R are energized while neither the line-relay- R nor thesupervisory relay r are operated. Upon the response of the calledsubscriber, however, these conditions are changed to the extent that thesupervisory relay r now responds to effect the opening of the circuit ofthe lamp S During conversation the battery B furnishes current to theline L for transmission purposes and for the operation of the variousrelays associated therewith. The

operatingcurrent. At the termination of the conversation when thereceivers are returned to their hooks the tip supervisory re lays r andr are deenergized and the lamps S and S energized. As before pointedout, the cut-off relay R and the sleeve supervisory relays remainenergized, while the line-relays do not respond and the line-signals arenot lighted. The operator observing the signals takes down theconnection and restores all parts to normal position. It will beunderstood that any other substation instruments adapted forcomn1on-battery transmission may be employed, that the several groundsreferred to at the central office are usually one and the same, or theymay be the COIIllDOIl-Ofl'lCG return, and that the batteries shown arepreferably common to the exchange.

I claim 1. In a telephone system, the combination with a telephone-line,of a line-relay and a source of current connected therewith, a cutoffrelay adapted when operated to connect one side of the line with onecontact of the jack, a cord-circuit to establish connections with theline, and a supervisory relay associated with the cordcircuit andadapted to be connected in shunt with said line-relay during the timewhen a connection is established, said cut-oii relay being also operatedwhen a connection is made, substantially as described.

2. In a telephone system, the combination with a telephone-line, of aline-signaling device and a source of current normally connected withthe line, a cut-off relay adapted to be bridged across the line duringconversation, and a supervisory relay associated with the cord-circuitand adapted to shunt said line-signaling device during the time when aconnection is established with the line, sub stantially as described.

3. In a telephone system, the combination with a telephone-line, of aline-relay and a source of current normally connected therewith, acut-off relay for the line, a pair of supervisory relays one upon eachside of said source, and means for including one of said relays in alocal circuit with said source and the cut-off relaywhereby they areoperated during the time that the connection is established, the othersupervisory relay being arranged to shunt the line-relay whereby thelatter is rendered inoperative, substantially as described.

4. In a telephone system, the combination with a telephone-line, of aline-relay, and a source of current for the line, a cut-off relay, apair of supervisory relays for the line, means for including the saidsource, one of the supervisory relays and the said cut-off relay'in alocal circuit, said local circuit in cluding parallel branches, theline-relay belocated in one of said branches, and the the-other side ofthe circuit being'normally other supervisory relay in the other of saidlished, said 'cut-olf relay being operated at branches, substantially asdescribed.

5. In a telephone system, thecombination with a telephone-line, of ahigh-resistance I cutofi relay therefor, a cord-circuit, a super- 1visory relayassociated therewith, said supervisory relaybeing oflowresistance and having a'current flowing through its-coil whenever thecord is connected with a line, and being ad usted to respond to currentin the line during the time the subscribers instrumentis in use, but tobe irresponsive to the current through its 0011 when the llIlQ-CIICUlt;

is open, substantially as described.

6. In a telephone system, the combination With a telephone-line, of aplurality of springjacks or connection-terminals therefor, the

circuit being permanently connected with the line conductor, and thecontacts upon disconnected from the corresponding con-l ductor, and acut-off relay for the line inde- I pendently bridged thereacross andadapted when operated to connect said disconnected terminals with theline conductor, substantiallyas described.

7. The combination with a telephone-line,

of a high-resistance line-signaling device, a

cut-oif'relay'fortheline adaptedto be bridged across the talking-circuitduring conversation, a supervisory signaladapted to be connected inshunt of the line-signaling device during the time when a connection isestabthe same time to render the=line-signalinoperative, substantiallyas described.

8. In a telephone system, the combination with a plurality oftelephone-lines, a line-relay for each-of said lines, a cord-circuit toconnect said'lines together for conversation, two supervisory relays forsaid cord-circuit, one adapted to be connected in series, and the otherin parallel with said line-relay while the cord-circuit is connectedwith the line, substantially asdescribed.

9. I11 a telephone system, thecombination with'a telephone-line,ofalineand acut-off relay for saidiline, and means whereby current =will 'passthrough said line and cut-off relays inseries during connection withsaid line, substantially asrdescribed.

10. In-a telephone system, the'combination with a plurality oftelephone-lines, of a cord-circuit to connect said lines together forconversation, two supervisory'relays for said cord-circuit, a cut-offrelay for saidlin e ,r

adapted to be actuated in series with said-, f-

supervisory'relays and in parallel VVithODG cf;

said lines, substantially-as :described.

Signedby me at Chicago, county of Cook, State of Illinois, this 10thxdayof December, 1902.

HARRY G. WEBSTER.

